对于下列代码： public class Example{ String str=new String("java"); char ch[]={'d','b','c'}; public static void main(String args[]){ Example ex=new Example(); ex.change(ex.str,ex.ch); System.out.println(ex.str+" and "+ex.ch[0]); } public void change(String str,char ch[]){ str="world";ch[0]= 'b'; } } 输出结果是: ( ) A: javaandd B: javaand C: javaandc D: javaanda